During an acute infection, which of the following is likely to occur?

• A. Increase in total white cell count
• B. Decrease in total white cell count
• C. No change in total white cell count
• D. Immediate antibody production

Answer: (A)

During an acute infection, the body rapidly activates the innate immune response and pushes leukocytes, especially neutrophils, from the bone marrow into the bloodstream. This swift mobilization leads to leukocytosis, an increased total white blood cell count, as the immune system ramps up its first line of defense. Neutrophils are the key early responders to infection, so their surge contributes most to the rise in WBCs. Antibody production belongs to the adaptive immune response and typically begins days after the onset of infection, so it is not immediate in the early phase. A decrease or no change in white blood cells would be inconsistent with the active recruitment of immune cells during acute infection.